My mother was 78 when she had radiation and chemo for oral cancer. It was no picnic for her and I'm sure her age played a part. She had some really bad days, some days she would have just have given in if she hadn't had her children pushing her. She survived the radiation and later she had extensive surgery to remove more than 1/2 her tongue, jaw and floor of mouth, because the cancer recurred. She is now 80 has been cancer free for over a year and is living on her own and doing quite well. She even drives herself places. Not like she used to, but that is part of being 80 also. She is still as sharp as ever and her sense of humor has stayed with her throughout. There are many side effects from her ordeal,like slurred speech and eating difficulties, but she is glad she fought the disease and is still kicking. Like I said it was very tough for her, but she's still here and all in all doing very nicely. I wish you and your mother the very best of luck and she can pull it off with a lot of support from her family.